Amine-containing cement processing additives

ABSTRACT

Exemplary cement processing aid compositions comprise a diamine, such as tetrahydroxylethylethylene diamine and an alkanolamine, such as triethanolamine or triisopropanolamine, to provide superior grinding efficiency.

FIELD OF THE INVENTION

The present invention relates to a cement processing aid, and moreparticularly to a composition comprising an amine and a diamine forenhancing grinding efficiency.

BACKGROUND OF THE INVENTION

Various substances have been known as agents for enhancing the strengthof cement cured products, such as mortar and concrete, in which portlandcement, mixed cement, etc., has been used. For example, French PatentApplication No. FR2485949A1 described the use oftetrahydroxylethylethylene diamine (referred to hereinafter as “THEED”)and other similar derivatives of ethylene diamine as cement grindingaids. Grinding efficiency and strength (especially at 28 days) weretaught to be better with these materials than with triethanolamine(referred to hereinafter as “TEA”). Also disclosed were reactionproducts with acetic acid and butylphosphoric acids.

U.S. Pat. No. 4,401,472 disclosed the use of poly(hydroxyalkylated)polyethyleneamine, poly(hydroxyethyl)polyethyleneimine, or mixtures ofthese used as additives in a cement mix that could include hydrauliccement, aggregate, and water. These additives were deemed to function asstrength enhancers for the cementitious mix.

U.S. Pat. No. 5,084,103 disclosed triisopropanolamine and othertrialkanolamines used as strength enhancing additives for later agestrength (7-28 days). These additives could be admixed with cementpowder or interground as a grinding aid during finish milling of thecement clinker.

U.S. Pat. No. 6,290,772 disclosed the use of hydroxylamines includingN,N-bis(2-hydroxyethyl)-2-propanolamine andN,N-bis(2-hydroxypropyl)-N-(hydroxyethyl)amine, to enhance thecompressive strength of the cement compositions after 1, 3, 7, and 28days. Also disclosed was a mixture involving other hydroxylamines suchas triethanolamine. The patent further taught that these amines could beadded as grinding aids in the manufacture of cement.

SUMMARY OF THE INVENTION

Exemplary cement processing compositions of the present inventioncomprise a diamine, such as tetrahydroxylethylethylene diamine(“THEED”), and an alkanolamine, such as triethanolamine (“TEA”). Thesecompositions provide superior performance as cement processing aids interms of grinding efficiency.

Exemplary cement processes of the invention comprise introducing adiamine and alkanolamine into a grinding operation in which cementclinker is ground into cement particulates. The invention also relatesto cementitious compositions made by such processes. The compositioncomprise a cementitious binder and the afore-mentioned processing aidcompositions.

Still further exemplary compositions of the invention, useful as cementgrinding aids or admixture compositions, comprisetetrahydroxylethylethylene diamine and diethanolisopropanolamine,optionally with triethanolamine, for providing early strength to cement.

Further advantages and features of the invention are described infurther detailed hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a comparative graphic illustration of grinding efficiency,using Type I cement processed at 66 tones per hour, of various amineblends in comparison with an exemplary TEA/THEED blend of the invention;and

FIG. 2 is a graphic illustration of grinding efficiency, using Type IIIcement processed at 48 tons per hour, of various amine blends incomparison with an exemplary TEA/THEED blend of the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Portland cement clinker is prepared by sintering a mixture of componentsincluding calcium carbonate (as limestone), aluminum silicate (as clayor shale), silicon dioxide (as sand) and miscellaneous iron oxides.During the sintering process, chemical reactions take place whereinhardened nodules, commonly called clinkers, are formed. After theclinker has cooled, it is pulverized together with a small amount ofgypsum (calcium sulfate) in a finish grinding mill to provide a fine,homogeneous powdery product known as Portland cement. Thus, an exemplarymethod of the invention for enhancing a cement grinding process,comprising: introducing, into the grinding of cement clinker to producecement, an ethylene diamine or derivative thereof; and an alkanolamine.

Cementitious compositions prepared by processes of the invention thuscomprise primarily cement made from cement clinker. Accordingly, suchcompositions preferably have at least 40% by weight of Portland cement,and more preferably at least 80%. Secondary argillaceous or pozzolanicmaterials may also be mixed with the cement clinker, such as clay,natural pozzolan, flyash, limestone, granulated blast furnace slag, or amixture thereof, to provide a hydratable cementitious composition.

It is believed that the cement processing aid compositions of thepresent invention, and processes employing such compositions, aresuitable for use on conventional cement grinding mills, includingwithout limitation ball mills and mills having rollers (the latter beingdescribed, for example, in U.S. Pat. No. 6,213,415 of Cheung,incorporated herein by reference).

Exemplary cement processing aid compositions of the present inventioncomprise tetrahydroxylethylethylene diamine (“THEED”) and at least onealkanolamine such as triethanolamine (“TEA”) or triisopropanolamine(“TIPA”). In preferred compositions, the ratio of THEED:TEA orTHEED:TIPA is from 99.5:0.5 to 0.5 to 99.5, and more preferably from95:5 to 5:95. The dosage by weight on cement can range from 0.001% s/sto 0.5% s/s, with the preferred range being 0.01% to 0.1% s/s.

The cement material of the present invention contains at least theabove-mentioned additive for cement materials and cement. It can alsocontain the above-mentioned additive for cementitious materials,aggregate, and cement. It can further contain other filler materialssuch as limestone, etc. The lower limit of the content of additive forcementitious materials of the present invention (weight ratio to totalweight) is 0.001 wt %, particularly 0.01 wt %, and the upper limit ofthe same is 0.2 wt %.

The method of adding the additive (the amine and diamine agents) forcementitious materials of the present invention is, for instance,addition during the cement production process. For example, these can beadded during pulverization of the mixture of cement clinker, gypsum,limestone, and other such fillers. They can also be added afterpulverization. In addition, the additives can be added as each fillermaterial is being ground individually. Moreover, they can also be addedafter this grinding process. The same is true in the case of using theadditives during concrete filler material production, such as productionof limestone powder, etc. When the additives of the present inventionare added during concrete or mortar production, they can be added to anyone of the materials or to several of the materials that will be used.They can also be added during mixing.

The amine/diamine additives for cement materials of the presentinvention can be concomitantly used with other additives, such asretarders, corrosion inhibiting agents, anti-foaming agents, AE agents,water-reducing agents, AE/water-reducing agents, high-performancewater-reducing agents, high-performance AE water-reducing agents,fluidizers, agents to reduce segregation, set accelerators, antifreezingagents, cold-resisting agents, shrink reducing agents, heat of hydrationinhibitors, alkali aggregate reaction inhibitors, granulated blastfurnace slag, fly ash, silica fume, natural pozzolan, expansive agents,and/or zeolite, etc.

The following examples are provided for the purposes of illustrationonly, and are not intended to limit the scope of the invention.

In four industrial ball mills which are used for the grinding of cement,combinations of THEED tetrahydroxyethylethylene diamine (hereinafter“THEED”) and triethanolamine (hereinafter “TEA”) or diethylene glycol(hereinafter “DIEG”) were compared to other additives for their effectin enhancing grinding efficiency. These other additives includedtriethanolamine acetate, as well as combinations ofN,N-bis(2-hydroxyethyl)-2-propanolamine (hereinafter “DEIPA”) witheither DIEG or TEA.

Both TEA (acetate) and DIEG are known cement grinding aids. Blends ofDEIPA with TEA or DIEG often give slightly enhanced performance comparedto TEA acetate or DIEG alone.

In all four ball mills, blends of THEED with TEA gave evidence of anunexpectedly enhanced performance as grinding aid additives. The presentinventor believes that the performance enhancement was also surprisingin that it was superior to additives containing DEIPA, which hashitherto been among the better grinding aid enhancers.

In most cases, observed performance in terms of grinding efficiency isfor the most part translated as finer ground particle size expressed ashigher Blaine (cm²/g). In two of these cases, where Blaine fineness wascontrolled, other evidence of superior grinding efficiency was notedrelated to measures taken to control the ball mills to produce uniformcement fineness (Blaine).

EXAMPLE 1

Type I cement is ball milled at a rate of 66 tons per hour. When thecombination of TEA and THEED were introduced to the grinding of cementclinker in the ball mill, the efficiency conferred upon the grindingprocess, which is assessed by measuring the cement fineness (Blainecm²/g) of the cement processed per dosage of grinding aid, was evaluatedand found to be superior to that provided by other grinding aid blends.

An 87% correlation (adjusted R² by regression analysis) was calculatedto exist between total grinding aid dosage and cement fineness (Blaine)for the set of data (excluding TEA/THEED data point) with a P-valueunder 0.05. This meant that for data points (other than for TEA/THEEDcombination), 87% of the effect of Blaine fineness was could beattributed to total grinding aid dosage, even though the data point forTEA-acetate had the lowest resultant Blaine per grinding aid dosage.

When the data point for TEA/THEED is included in the regressionanalysis, the correlation between grinding aid dosage and Blaine dropsto 6.4%, with a P-value of 0.34, meaning that Blaine is not justdependent upon grinding aid dosage once this data point is introducedinto the analysis. Only 6.4% of the additive's effect on Blaine finenesscan be explained by additive dosage alone. The blend of TEA/THEED isproducing a unique effect in increasing Blaine fineness, beyond thedosage effect. In examples 3 and 4, increased production for TEA/THEEDis demonstrated by either decreased tailings (coarse material returningto the mill for further grinding), or increased feed rate on the mill.Both of these parameters were relatively constant for TEA/THEED comparedto other additives tested. (Elevator amps is the energy required, interms of electric amperage required for moving tailings material (e.g.,coarse material) back up to the mill for regrinding). Blaine fineness,clinker feed rate, tailings, and extent of separator opening are allinterdependent parameters related to mill production. A favorableindication for production is often noted for only one of theseparameters with the other parameters held constant. In this example, aswell as example 2, increased Blaine fineness is the indicator offavorable production, while in examples 3 and 4, Blaine fineness is heldconstant, yet favorable production is reflected by a change in one ofthe other parameters.

For each sample tested, clinker feed and elevator amps is shown inTable 1. TABLE 1 At sample time Clinker feed elevator ton/hr ampsTEA-acetate 64.0 35.0 TEA/DEIPA 62.5 32.4 DIEG/DEIPA 64.7 30.5DIEG/THEED 64.0 33.0 TEA/THEED 64.0 34.0 TEA-acetate#2 64.0 34.5

There is a second TEA-acetate data point whereby the Blaine finenessfell far below that of the other tests. It is unknown why this Blainewas so low. It was the first data point taken during the day.

The results of the TEA/THEED combination, in comparison with othercombinations, are shown in the graph of FIG. 1. Blaine vs. GA dosage isplotted for each grinding aid formulation. The plotted line is a linearbest fit for all points excluding TEA-THEED, and TEA-acctate#2. TheTEA-THEED formulation had the highest Blaine per grinding aid dosage.This data point is significantly far away from the linear relationshipestablished for Blaine vs grinding aid dosage for the other formulations(excluding TEA-acetate #2).

EXAMPLE 2

Analysis on this second mill grinding type III cement processed at therate of 48 tons per hour revealed that there existed a correlationbetween Blaine fineness dosage when TEA/THEED and TEA-acetate areexcluded from the analysis (64%). This means that the remaining group ofadditives have about the same grinding effect, and that cement finenessas measured by Blaine (cm²/g) is dependent upon grinding aid dosage. Thegrinding effect of TEA-acetate is outside of this correlation, bringingthe correlation of all points except for TEA/THEED down to 14%. Thegrinding effect of TEA-acetate is inferior to that of TEA/DEIPA,DIEG/THEED, and Glycol/DEIPA.

TEA/THEED had a measureably superior effect on grinding efficiency.Whether TEA/THEED is included in a group containing TEA-acetate or not,the correlation between dosage and Blaine is 0%, meaning that thegrinding effect of TEA/THEED is unique compared to these otheradditives, and superior. TABLE 2 Mill 3 Correlation Pts includedAdjusted R2 P-value All 0% 0.83 All except TEA-THEED 14% 0.35 All exceptTEA-THEED 64% 0.28 and TEA-acetate All except TEA-acetate 0% 0.82

The effect of grinding aid dosage on Blaine fineness is illustrated inFIG. 2. Blaine vs. GA dosage is plotted for each grinding aidformulation. The plotted line is a linear best fit for all pointsexcluding TEA-THEED. The TEA-THEED formulation had the highest Blaineper grinding aid dosage. This data point is significantly far away fromthe linear relationship established for Blaine vs grinding aid dosagefor the other formulations.

Regarding the other parameters related to grinding efficiency, bothDIEG/DEIPA and DIEG/THEED show a decrease in elevator amps, as doesTEA/THEED, when compared to TEA-acetate. Clinker feed for all additivestested is within 1 ton/hr. TABLE 3 At sample time Clinker feed elevatorton/hr Amps TEA-acetate 44 45 TEA/DEIPA 42 42 DIEG/DEIPA 43 35DIEG/THEED 43 35 TEA/THEED 43 35

EXAMPLE 3

In another cement grinding mill, wherein Type I cement is processed at arate of 50 tons per hour, Blaine fineness had a linear correlation withgrinding aid dosage, and based on this analysis TEA/THEED did not emergeto be a superior product. The adjusted R2 for the regression analysis ofthe data in this set was 69.5% with a P value of 0.05. Yet data outputobtained for this mill showed that the average material returned to themill by the separator was the lowest for TEA/THEED. This is reflected bythe low reading for the tailings impact flow meter and the low grindingperformance ratio (GPR). The lower the GPR for the same feed, the lowerthe material being returned to the mill from the separator. The lowertailings and GPR for TEA/THEED are particularly significant whencomparing TEA/THEED to TEA-acetate, both with equal total feed rates.TABLE 2 Mill @ ˜50 total tailings grinding ton/hr, Additive Blaine feedimpact flow performance type I cement ppm cm2/g ton/hr meter - tph ratioTEA-acetate 403 3883 50.5 199.7 2.42 DIEG/THEED 480 3940 47.5 197.4 2.62TEA/THEED 399 3808 50.6 161.9 1.66 TEA/DEIPA 350 3808 45.0 165.0 2.20DIEG/DEIPA 475 4026 53.2 174.0 1.76

EXAMPLE 4

In a fourth mill processing Type II cement at a rate of 30 tons perhour, all of the data, including TEA/THEED showed a linear correlationbetween grinding aid dosage and Blaine, wAith an adjusted R2 of 72.5%and a P-value of 0.096. When the TEA/THEED sample was taken, the totalclinker and gypsum feed to the mill was 33.5 ton/hr. The clinker andgypsum feed for TEA-acetate was 30.9 ton/hr. The clinker and gypsum feedfor all other additives tested was somewhere in between these values.High allowed feed rate with TEA/THEED indicates a high grindingefficiency for the additive.

EXAMPLE 5

Further testing was done on mixtures of tetrahydroxylethylethylene(THEED) and diethanolisopropanolamine (DEIPA). First, blank samples ofcement mortar, using type 1 cement from the U.K., was mixed with waterand cured. One day average strength for five samples (control) wasdetermined to be 19.2 MPa (megapascals). Next, cement mortars containingTHEED and DEIPA, each at 25 ppm (based on weight of cement), weretested. One day strength for the combination was determined to be 109%of the control, 112% of THEED alone, and 114% of DEIPA alone. One daystrength was determined to be 111% of 50 ppm DIEPA. The results arecontained in Table 3 below: TABLE 3 1 day strength THEED DEIPA (Mpa) ppmppm Average 19.2 25 18.4 25 18.9 Average 18.7 25 18.3 25 25 20.9 25 18.8

The experiment was then repeated with 20 ppm THEED and 50 ppm DEIPA. Oneday strength for the combination was determined to be 114% of thecontrol, 107% of THEED alone, and 113% of DEIPA alone. The results arecontained in Table 4 below: TABLE 4 1 day strength THEED DEIPA (Mpa)Average 18.6 20 20.0 50 18.8 20 50 21.3

The experiment was repeated this with 10 ppm THEED and 25 ppm DEIPA. Oneday strength for the combination was determined to be 115% of thecontrol, 112% of THEED alone, and 120% of DEIPA alone. The results aretabulated in Table 5 below: TABLE 5 1 day strength THEED DEIPA (Mpa)Average 19.1 10 19.7 25 18.3 10 25 22.0

Thus, from the foregoing data, it was determined that blends of 25%THEED and 75% DEIPA were preferred for improving early strength whenadmixed into in cementitious compositions. Accordingly, a preferredcomposition of the invention, for admixing into a cement composition, orindeed for adding into a cement intergrinding process, comprises THEEDin the amount of 20-30% and DEIPA in the amount of 70-80% by weight oftotal composition.

Further exemplary compositions of the invention comprise a blend ofTHEED (e.g., 28-38%), DEIPA (53-63%), and TEA (9-19%), with blends ofTHEED (33%), DEIPA (8%), and TEA (58%) considered optimum for providingstrength enhancement to cements and concretes.

The foregoing is provided by way of illustration and is not intended tolimit the scope of the invention.

1. (canceled)
 2. (canceled)
 3. (canceled)
 4. (canceled)
 5. (canceled) 6.(canceled)
 7. A method for grinding cement to enhance the cement when itis admixed into a composition comprising: introducing, into the grindingof cement clinker to produce cement, tetrahydroxylethylethylene diamineor derivative thereof and an alkanolamine selected from the groupconsisting of triethanolamine, triisopropanolamine, anddiethanolisopropanolamine, the ratio of said tetrahydroxylethylethylenediamine to said alkanolamine being 95:5 to 5:95 based on weight, and thedosage of said amines to cement being 0.001% s/s to 0.5% s/s. 8.(canceled)
 9. A composition provided by the method of claim
 7. 10.(canceled)
 11. The method of claim 7 wherein the dosage of said aminesto cement is 0.01% s/s to 0.1% s/s.
 12. (canceled)
 13. The compositionof claim 9 wherein said tetrahydroxylethylethylene diamine is present inthe amount of 20-30% and said diethanolisopropanolamine is present inthe amount of 80-70%, said percentages based on total weight of saidcomposition.
 14. The composition of claim 13 comprising triethanolamine.15. (canceled)
 16. The method of claim 7 comprising incorporating, intothe grinding of cement clinker, tetrahydroxylethylethylene diamine inthe amount of 28-38%, triethanolamine in the amount of 9-19%, anddiethanolisopropanolamine in the amount of 53-63%, said percentagesbased on weight of total amines.
 17. The method of claim 7 wherein theincorporation of said tetrahydroxylethylethylene diamine andtriethanolamine enhance Blaine fineness of cement produced from thegrinding of said cement clinker above additive dosage of said amineswhen incorporated separately.
 18. The method of claim 7 wherein saidgrinding of said cement clinker occurs in closed-circuit grindingwherein coarse ground material is returned into the mill for furthergrinding, the incorporation of said tetrahydroxylethylethylene diamineand triethanolamine decrease the amount of coarse material returned tothe mill for further grinding.
 19. The method of claim 7 wherein saidincorporation of said tetrahydroxylethylethylene diamine andtriethanolamine enhances strength of the cement.